An extensive body of work on visual search has established much about the fundamental properties of visual attention. Yet, several critical questions remain unanswered and under-explored. The three Specific Aims of this proposal are designed to collectively explore influences of external factors on visual search performance, specifically in the domain of rare-target search. To further the understanding of search and visual cognition more generally, these experiments test the effects of experience, perceptual salience, and environment on rare-target visual search. Specific Aim #1 investigates the effects of expertise on search performance. Performance of videogame experts and novices on a rare search task will be compared to directly explore how experience differentially utilizes top-down and bottom-up processing for rare-target search. Videogame experience has previously been shown to predict enhanced performance on numerous visual attention tasks and the results of the current study may ultimately reveal ways in which specific training regimens could be used in the rehabilitation of patients with perceptual deficits. Specific Aim #2 examines both how added decision-making processes as well as the perceptual properties of the search items interact with the low-prevalence effect. Here we introduce a multiple target search to the low-prevalence paradigm, and examine how multiple targets, varying in both salience and prevalence, will modulate low-prevalence effects. Finally, Specific Aim #3 examines how search processes are specifically impacted by depleted attentional resources when all other aspects of the task are held constant. Attentional resources are consumed in the proposed experiment by a non-task-related source, induced psychosocial stress, which promises to illuminate the dependence of visual search performance on attentional resources as well as the relationship more generally between stress and visual attention. The proposed research program offers several novel approaches for targeted health rehabilitation. Building upon prior research which has demonstrated improved performance for the elderly after experience with high-speed, fast reaction time tasks, the current project may reveal ways in which videogame playing can alter both perception and attention, directly modifying cognitive abilities in a manner that may be useful in rehabilitating accident victims with decreased perceptual and motor skills. Furthermore, this project explores the effects of psychosocial stress on visual perception and attention, promising to illuminate how performance in population's particularly vulnerable to psychosocial stressors may be adversely affected. [unreadable] [unreadable] [unreadable]